"Optoelectronics and E&M" section would cover devices like lasers, LEDs, modulators, paasive and active optical communication elements as well as RF and microwave elements.
We encourage you to post anything related to this topic that you feel would be instructive, informative, fun, encouraging or anything that you feel would be technicaly interesting for electronics enthusiasts. Please feel free to post web links, journal articles, magzine links, news articles, product announcements, company links or anything on similar lines.
Please keep this forum technical in nature.
I suggest EcE students, regardless of their specialization, to visit
http://www.spie.org/Membership/index.cfm?fuseaction=TG_Nanotechnology
and explore current activities in nanotechnology. Another excellent resource is
Posted by: Akhlesh Lakhtakia on August 25, 2004 11:48 AMPhotonic Crystals
Probably the most hyped-up topic in the entire domain of optics/electromagnetism/opto-electronics in recent times is that of photonic crystal or sometimes called photonic bandgap artificial material system (PBG) in direct analogy to crystaline 'electronic band gap' materials like Si and GaAs. Most important group of contributors in this area is Prof John Joannopoulos group in MIT and Axel Scherer
of CalTech. Following is excellent bunch of tutorials and resource material for any beginner into this exciting world of integrated optoelectronics.
MIT PBG Group
Recommendations from Prof Akhlesh Lakhtakia, Penn State Univ
I would strongly advise EcE students to pay attention to nanotechnology; specifically, quantum dots, carbon nanotubes, molecular motors, sculptured thin films, vapor deposition techniques, self-assembly methods, layer-by-layer deposition, simulation of low- and high-mobility growth, and so on. Another significant area is electromagnetic compatibility, particularly in submicron structures. Finally, think in terms of femtoseconds and attoseconds; i.e., ultarwideband devices.
Posted by: Akhlesh Lakhtakia on July 17, 2004 05:49 AM
OLED TV Gets Ready For Prime Time
Author:- BETHANY HALFORD
Source:- ACS Publications
Philips shows off its 13-inch prototype organic light-emitting diode (OLED)
television this week at the Society for Information Display's International
Symposium in Seattle. OLED displays offer several advantages over flat-panel
liquid-crystal displays. In particular, they feature a wide viewing angle,
can be made less than 2 mm thick, and can be manufactured in the open air
using an ink-jet printing process. Several companies are pursuing the technology.
Last week, Seiko Epson broke the OLED display size record when it unveiled
its 40-inch, full-color prototype.
An Interesting Article on History of Optical Pumping
To read an intersting history on discovery/invention and development of various applications of "optical pumping" click here
Silicon Optical Modulator Achieves >1-GHz Operation
In a development that points to the advent of silicon as a viable photonic material, a group of scientists from Intel Corp. in Santa Clara, Calif., and in Jerusalem has fabricated an all-silicon optical modulator with a modulation frequency greater than 1 GHz. A report of the work appears in the Feb. 12 issue of Nature and suggests further avenues of inquiry that may enable such a device to achieve higher performance, point-ing to potential advances in optical circuits.
Until now, silicon largely has resisted efforts to utilize it as an optical modulator because of its material properties. Specifically, unlike electro-optic materials such as lithium niobate and potassium dihydrogen phosphate, silicon does not exhibit the Pockels effect, in which the application of an electric field induces a linear change in the refractive index of the material. Silicon-based modulators have been demonstrated that rely on the introduction of free carriers to modify the refractive index, but this phenomenon is relatively slow and, until now, has limited such devices to modulation frequencies of only about 20 MHz.
The Intel optical modulator also employs the free-carrier plasma dispersion effect, but it crucially adopts a new means of doing so: the introduction of a 2.5-mm-long metal-oxide-semiconductor capacitor phase shifter into one arm of a silicon asymmetric Mach-Zehnder interferometer. The phase shifter consists of 900-nm-thick P-type polysilicon atop 1.4-µm-thick N-type crystalline silicon and separated by a 12-nm-thick insulating oxide layer.
The application of a positive voltage to the P-type polysilicon causes a 10-nm-thick charge layer to accumulate on either side of the oxide -- electrons in the N-type silicon and holes in the P-type polysilicon -- that changes the effective refractive index of the silicon waveguide. This induces a phase shift in the 1.55-µm radiation propagating through that arm, which leads to interference in the output region of the interferometer.
Using a pseudorandom electrical input to the phase shifter, the researchers verified that the modulator supports optical data transmission rates of 1 Gb/s. They expect that the modulation frequency can be scaled to 10 GHz and are investigating means of reducing on-chip loss in the device, such as by replacing the polysilicon with single-crystal silicon.
Reference:- Nature; 2004 Feb 12;427(6975):595-6
Authors:- Liu A, Jones R, Liao L, Samara-Rubio D, Rubin D, Cohen O, Nicolaescu R, Paniccia M.
Contact:- Intel Corporation, 2200 Mission College Blvd, CHP3-109, Santa Clara, California 95054, USA. ansheng.liu@intel.com
Institute of Technology, Banaras Hindu University
Varanasi 221005 INDIA